Use of the Cone Expansion Test to Assess the Potential for Longitudinal Seam Failure in Extruded AZ31 and AM30 Mg Alloy Tubes

Magnesium generally has limited ductility which, in the case of extruded tubes, may be further reduced at the extrusion seams. These are locations where the material flow separates and rejoins during extrusion and are unavoidable when a hollow profile product is continuously extruded. When this type of magnesium tube is stressed along the circumferential direction, as in hydroforming, tube ruptures consistently occur along the extrusion seams. …